Source : Webster's Revised Unabridged Dictionary (1913)

Papilionaceous \Pa*pil`io*na"ceous\, a.
   1. Resembling the butterfly.

   2. (Bot.)
      (a) Having a winged corolla somewhat resembling a
          butterfly, as in the blossoms of the bean and pea.
      (b) Belonging to that suborder of leguminous plants
          ({Papilionace[ae]}) which includes the bean, pea,
          vetch, clover, and locust.